The transverse structure of the QCD string

The characterization of the transverse structure of the QCD string is discussed. We formulate a conjecture as to how the stress-energy tensor of the underlying gauge theory couples to the string degrees of freedom. A consequence of the conjecture is that the energy density and the longitudinal-stress operators measure the distribution of the transverse position of the string, to leading order in the string fluctuations, whereas the transverse-stress operator does not. We interpret recent numerical measurements of the transverse size of the confining string and show that the difference of the energy and longitudinal-stress operators is the appropriate probe to use when comparing with the next-to-leading order string prediction. Secondly we derive the constraints imposed by open-closed string duality on the transverse structure of the string. We show that a total of three independent `gravitational' form factors characterize the transverse profile of the closed string, and obtain the interpretation of recent effective string theory calculations: the square radius of a closed string of length \beta, defined from the slope of its gravitational form factor, is given by (d-1)/(2\pi\sigma)\log(\beta/(4r_0)) in d space dimensions. This is to be compared with the well-known result that the width of the open-string at mid-point grows as (d-1)/(2\pi\sigma) log(r/r_0). We also obtain predictions for transition form factors among closed-string states.Comment: 21 pages, 1 figur

Cutoff Effects on Energy-Momentum Tensor Correlators in Lattice Gauge Theory

We investigate the discretization errors affecting correlators of the energy-momentum tensor $T_{\mu\nu}$ at finite temperature in SU($N_c$) gauge theory with the Wilson action and two different discretizations of $T_{\mu\nu}$. We do so by using lattice perturbation theory and non-perturbative Monte-Carlo simulations. These correlators, which are functions of Euclidean time $x_0$ and spatial momentum ${\bf p}$, are the starting point for a lattice study of the transport properties of the gluon plasma. We find that the correlator of the energy $\int d^3x T_{00}$ has much larger discretization errors than the correlator of momentum $\int d^3x T_{0k}$. Secondly, the shear and diagonal stress correlators ($T_{12}$ and $T_{kk}$) require \Nt\geq 8 for the $Tx_0={1/2}$ point to be in the scaling region and the cutoff effect to be less than 10%. We then show that their discretization errors on an anisotropic lattice with \as/\at=2 are comparable to those on the isotropic lattice with the same temporal lattice spacing. Finally, we also study finite ${\bf p}$ correlators.Comment: 16 pages, 5 figure

One dimensional parabolic free boundary problems

The method of lines is used to approximate explicit and implicit free boundary problems for a linear one dimensional diffusion equation with a sequence of free boundary problems for ordinary differential equations. It is shown that these equations have solutions which can be readily obtained with the method of invariant imbedding. It also is established for a model problem that the approximate solutions converge to a unique weak and (almost) classical solution as the discretization parameter goes to zero

A New Approach to Climate Change: A Consideration of Ancillary Benefits in Linking Regional Permit Trading Systems

In this paper, I investigate the economic efficiency of two major approaches to greenhouse gas reduction, and evaluate their respective benefits. First, I trace the path of action and thinking on addressing climate change from a global to a regional level. Second, I consider the major economic benefits of having a globally-integrated greenhouse gas abatement system. Third, I consider the economic benefits of regional approaches to climate change, with a focus on the ancillary benefits from greenhouse gas abatement. I conclude by reviewing the challenges to linking regional abatement systems into a cohesive network, and suggest a potential future approach to an economically-efficient abatement of greenhouse gas emissions

Biological Characteristics That Make The Lesser Peachtree Borer (Lepidoptera: Sesiidae) a Pest on Peach Trees

The lesser peachtree borer, Synanthedon pictipes, is a native insect with well distributed hosts near peach orchards, which has high mobility between sylvatic and domestic hosts. It is able to take advantage of the susceptibility of the peach tree to periodic freeze injury and disease cankers. The moth stage is present through most of the growing season and effectively conceals the eggs singly at the most favorable sites for larval success

The use of paper honeycomb for prototype blade construction for small to medium-sized wind driven generators

Paper honeycomb is used for the construction of conventional, propeller-type, windmill blades. Using fairly simple techniques and conventional power tools, it is possible to shape both simple foils and more complex foils with or without tapered plan forms and with or without varying profiles. A block of honeycomb, in its compressed form, is mounted on a wedge and run through a bandsaw with the table at an appropriate tilt angle. It is the combination of the wedge angle and the table angle that gives the tapered planform and profile shape. Next the honeycomb is expanded on the shaft and jigged to give the desired angles of attack. With the honeycomb fixed in position, the blade is covered with a fine weave fiberglass cloth. Any surface quality can then be achieved with filling and sanding